Water Stress Increases Winter Injury - Leucaena leucocephala Distance from runoff water (m) Dieback (% of maximum)

Tree nutrition / vs Winter Injury Winter Injury (%) Pecan Yield (kg/tree) %N /%P

Cold-hardiness of Lagerstroemia hybrids/ Johnson et al. SNA Res. Conf. 45:467:2000 Lowest Survival Temperature (C) AL = 32 o N. latitude DC = 37 o N. latitude

Root growth after planting/ Barnett wks 9 wks 0 wks Privet cm 15 cm Weeks after Planting Days without Water 21 wks 9 wks 0 wks cm 15 cm Well-watered Droughted

Compaction increases soil strength & decreases root growth Brais SSSAJ 65:1263: % Reduction No Growth Number of tractor passes Soil Strength (MPa) Fine-textured soilCoarse-textured soil BD (g/cc) Strength (MPa) No Growth

A History of Tree Planting in LC Timeline –1950s Mulberry –1960s Ash –1970s Afghan pine –1980s Oaks –1990s Chilean mesquite –2000s Chitalpa –2010s ?? Issues –Allergenic, water hog –1994-itis? Emerald ash borer? –Alleppo pine mite –Sudden Oak Death, Oak wilt? –Brittle branches, toppling –Frost/Drought cracks –“Plant it & they will come!!’

Bark Beetles

Apple Mimosa

Dormancy & Cold-hardiness Cold - Hardiness of Apple Blooms Dormant Silver Tip 12mm Green Green Tip Tight Cluster Full Pink Full Bloom Growing Degree Hours ( o C) LT 50 ( o C) Photos by:

Cold - Hardiness of Apple Blooms Growing Degree Hours ( o C) LT 50 ( o C) Apr12Apr17Apr22Apr29Apr2May1 Approximate Calendar Dates Untreated Sprinkled

Rules of Thumb A 1 o F increase, increases ET by 1% To reduce water use—reduce canopy coverage –Under nonstressed conditions, a full canopy uses the same amount of water, i.e. Kentucky bluegrass = pecan = mesquite, etc. –Management issues: growing season, level of stress tolerance Rain is a good thing—don’t waste it! –Clean irrigation water (300 mg/L) adds about 1 ton of salt per acre per year. Plants will use less than ½ of that.

Dormancy & Cold-hardiness Cold-hardiness of Lagerstroemia hybrids/ Johnson et al. SNA Res. Conf. 45:467:2000 Lowest Survival Temperature (C)

Dormancy & Cold-hardiness Bloom Delay of Apple Blooms Hour Temperature ( o C) ~115 GDH ~316 GDH

Frost Protection Requires Little Water Time of Day (hr) Bud Temperature ( o C) 4 to 20 mm/frost event

What’s Killing Your Trees Factors Affecting Acclimation-Size Spring Buds = -3 o Cambium = -4 o Roots = -4 o Seedling = -3 o Germinant = -2 o Winter Buds = -25 o Cambium = -50 o Roots = -10 o Seedling = -30 o

What’s Killing Your Trees Freeze Injury E. Shannon

What’s Killing Your Trees Freeze Injury Apple Pecan E. Shannon Eucalyptus Freeze Ring

Increased wind= windbreaks Increased drought= e.g. 4” in LC and more dead trees in low income areas: trees decrease violence in inner cities

J. Mexal What is wrong with this picture?

Pine Issues in Las Cruces Abiotic –Physcial Factors Temperature Moisture Biotic –Biological Disease Insect DPD- human Not Found in NM landscapes—Yet? White pine blister rust Sudden oak death (P. ramorum) Diplodia blight Pine knot nematode

Nebraska Forestry Service Pinus sylvestris Pine Knot Nematode on Scots Pine Native to Japan Discovered in 1979 in MO Carried by pine sawyer beetle No control

Dothistroma pini (Red band needle blight) [Small dark brown fruiting bodies]

Piñon Needle Scale (Matsucoccus acalyptus) Crawler Adult w/ Immature ‘Bean’ stage cals.arizona.edu/pubs/insects/az1315.pdf

E. Shannon Nantucket Pine Tipmoth This is a young tree affliction (<10 ft tall)

Phytopthora pinifolia on Pinus radiata / Michael J. Wingfield

Elevation (ft) Piñon Mortality (%)Stocking (% Piñon ) Piñon is moving up the hill/ after Ryerson 2006

What’s Killing Your Trees DPD = N. Goldberg

Climate Change in the SW US

Turf and Irrigation Affects Tilia cordata growth Stewart et al. HortSci 40(5):1529:2005 * * * * Leaf Area (m 2 )/ Diameter (mm) Turf Treatment NS = not stressed S = stressed

Global Temperature

Change in vegetation with climate change/ Aber et al. Biosci. 51(9):735:2001 Canadian Global Coupled ModelHadley Centre for Climate Prediction ΔT = 2.8CΔT = 5.2C

What’s Killing Your Trees Cold - Hardiness of Apple Blooms Approximate Calendar Date LT 50 ( o C)

Killing Trees Think before your plant!